I HAVE OWNED THIS KNUCKLE SINCE 1977, BOUGHT IT FROM MY COUSIN. MY COUSIN PURCHASED THIS BIKE IN 1960 OR 1961 WHILE TRAINING IN THE NAVY IN THE SAN FRANCISCO AREA. HE PURCHASED IT FROM A MOTORCYCLESHOP IN THE AREA, HE THINKS THAT IT AT ONE TIME WAS A S.F. POLICE BIKE. I NEED TO KNOW HOW TO TRACE THE HISTORY OF MY KNUCKLE FOR THE PURPOSE OF RESTORING IT. I THINK IF IT WAS ONCE A S.F.P.D. BIKE THAT WOULD BE A GREAT THEME FOR RESTORATION. ALL HELP WOULD BE APPRECIATED.